Bell Ringer 1 Please staple and turn in
Bell Ringer: 1) Please staple and turn in your mushy mantle lab in the silver tray. . 2) Take out the guided worksheet on heat transfer from your blue tub. Put it in your research divider and complete it. 8 minutes. Today’s Lesson: Continental Drift
(Drifting Continents) Objectives: 1. What is continental drift? 2. How do landforms, fossils, and climate changes show evidence of the changing surface of the Earth? 3. Explain how sea-floor spreading provides a way for continents to move.
Tech Terms: 1. Alfred Wegener – German scientist whom in the 1900’s hypothesized that the continents had once been a huge landmass which he called Pangaea (“all lands”).
Let’s fit the pieces of Wegener’s puzzle together! Old book p. 118 -122
2. continental drift – the slow movement of continents over Earth’s surface. It was a hypothesis, that was tested. Why did he believe in this theory? 3. fossil – any trace of an ancient organism that has been preserved in sedimentary rock.
Bell Ringer: Complete the back of yesterday’s Review Sheet Organizer! • Define and illustrate the following 3 terms: Old book p. 118 -122. • Pangea • Wegener • Disbelief
• Wegener used evidence from landforms, fossils, and climate to support his hypothesis. • Wegener’s hypothesis was rejected because he could not provide an explanation for the force that pushes and pulls the continents. • Where is the math? How can you recreate this experiment?
PBS Videos: Why Wegner began his hypothesis! • http: //www. pbslearningmedia. org/resource /ess 05. sci. ess. earthsys. wegener 1/platetectonics-the-scientist-behind-theory/
New Evidence to support his claims? • Cooling & Shrinking • Sea Floor Spreading • Molten Material and Magnetic Stripes • Convection Currents
So What’s Next? • How does convection current movement create continental drift? • Continental Drift inside the mantle (2 min) • TODAY’S Objectives! (p. 123) • What is a mid-ocean ridge? • How is Sea Floor Spreading Related?
n o i t c !! e s v t n en o C urr C n o i n! s u f o f i i D ers p s i D
Sea Floor-Spreading 1. mid-ocean ridge – longest chain of mountains extending into all of Earth’s oceans, that curves like the seam of a baseball along the sea floor.
2. sea floor spreading – the process that adds new material to the ocean floor at the mid-ocean ridge. Molten material erupts and spreads out through the valley that runs along the center of the mid-ocean ridge. It then pushes aside the rock that was already there.
It’s all about … CONVECTION CURRENTS!!!!!! Continental Drift inside the mantle (2 min)
3. deep ocean trench – this forms from subduction 4. Subduction- (the oceanic crust bends downward forming a deep underwater canyon on the ocean floor).
deep ocean trench examples
4. subduction – Part 2: when the ocean floor sinks beneath a deep ocean trench and gets swallowed by the mantle.
Alaska
• Sea-floor spreading and subduction can change the size and shape of the oceans. • The Pacific Ocean, aka The Ring of Fire, has lots of subduction zones, thus it is getting smaller. • The Atlantic Ocean is expanding!
Further Evidence of Continental Drift! • http: //www. pbslearningmedia. org/resource /ess 05. sci. ess. earthsys. wegener 2/platetectonics-further-evidence/
So what will happen as these plates in the ocean floor continue to spread? • Earth 100 Million Years from now • Convection Currents in the Earth. One more time, a different way! • Plate tectonics on a cocoa earth - You. Tube
- Slides: 25